无法使用 UICollectionVIewCell 数据加载 UIView
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【中文标题】无法使用 UICollectionVIewCell 数据加载 UIView【英文标题】：Can't load a UIView with UICollectionVIewCell data 【发布时间】：2017-08-29 16:12:14 【问题描述】：我到处寻找解决方案。通过写这个问题再次尝试我的运气。我有一个collectionViewCell，我在其中解析了一个包含名称和ID 的XML URL 数据。现在，当我点击单元格时，我想加载一个带有 AVPlayer 的 UIView。要播放文件，我必须使用不同的 URL，但使用我在该单元格中解析的 id。这是我的didSelectItem func：
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath)
let playerLauncher = PlayerLauncher()
playerLauncher.showPlayer()
这是我的 PlayerLauncher 文件：
import UIKit
import AVFoundation
class PlayerView: UIView
var item: Item?
override init(frame: CGRect)
super.init(frame: frame)
backgroundColor = UIColor.black
let id = item?.itemId
if let url = URL(string: "http://xample.com/play.m3u?id=\(id)")
let player = AVPlayer(url: url)
print(url)
let playerLayer = AVPlayerLayer(player: player)
self.layer.addSublayer(playerLayer)
playerLayer.frame = self.frame
player.play()
required init?(coder aDecoder: NSCoder)
fatalError("init(coder:) has not been implemented")
class PlayerLauncher: NSObject
func showPlayer()
if let keyWindow = UIApplication.shared.keyWindow
let view = UIView(frame: keyWindow.frame)
view.backgroundColor = UIColor.white
view.frame = CGRect(x: 0, y: keyWindow.frame.height - 50, width: view.frame.width, height: 50)
let playerFrame = CGRect(x: 0, y: 0, width: keyWindow.frame.width, height: keyWindow.frame.height)
let playerView = PlayerView(frame: playerFrame)
view.addSubview(playerView)
keyWindow.addSubview(view)
UIView.animate(withDuration: 0.5, delay: 0, usingSpringWithDamping: 1, initialSpringVelocity: 1, options: .curveEaseOut, animations:
view.frame = keyWindow.frame
, completion: nil)
我已经从我的 Item NSObject 类中设置了项目，但是在选择单元格后 UIView 加载正常但不播放文件并显示 id = nil。我该如何解决？
更新：所以我稍微改变了我的代码，我可以得到 id 来打印。
以下是我在didSelectItem 方法中所做的更改：
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath)
collectionView.deselectItem(at: indexPath, animated: true)
let playerView = PlayerView()
playerView.item = items?[indexPath.item]
let playerLauncher = PlayerLauncher()
playerLauncher.showPlayer()
在此之后，我更改了 PlayerView 和 PlayerLauncher 类中的一些代码：
import UIKit
import AVFoundation
class PlayerView: UIView
var id: String?
var item: Item?
didSet
id = item?.itemId
print(id)
override init(frame: CGRect)
super.init(frame: frame)
backgroundColor = UIColor.black
func startPlaying()
if let url = URL(string: "http://xample.com/play.m3u?id=\(id)")
let player = AVPlayer(url: url)
print(url)
let playerLayer = AVPlayerLayer(player: player)
self.layer.addSublayer(playerLayer)
playerLayer.frame = self.frame
player.play()
required init?(coder aDecoder: NSCoder)
fatalError("init(coder:) has not been implemented")
class PlayerLauncher: NSObject
func showPlayer()
if let keyWindow = UIApplication.shared.keyWindow
let view = UIView(frame: keyWindow.frame)
view.backgroundColor = UIColor.white
view.frame = CGRect(x: 0, y: keyWindow.frame.height - 50, width: view.frame.width, height: 50)
let playerFrame = CGRect(x: 0, y: 0, width: keyWindow.frame.width, height: keyWindow.frame.height)
let playerView = PlayerView(frame: playerFrame)
view.addSubview(playerView)
keyWindow.addSubview(view)
UIView.animate(withDuration: 0.5, delay: 0, usingSpringWithDamping: 1, initialSpringVelocity: 1, options: .curveEaseOut, animations:
view.frame = keyWindow.frame
, completion: (completeAnimation) in
playerView.startPlaying()
)
现在我可以从didSet 打印ID，但是在startPlaying() 方法中，当我选择该项目时它仍然显示id = nil。如何在init 或startPlaying() func 中获取didSet 中设置的属性？
【问题讨论】：
【参考方案1】：您可能希望在选择单元格时检索Item 信息。
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath)
let item: Item = itemList[indexPath.item] // just for instance
let playerLauncher = PlayerLauncher()
playerLauncher.showPlayer(item)
因此您需要更改您的Player，如下所示：
class PlayerLauncher: NSObject
func showPlayer(item: Item)
if let keyWindow = UIApplication.shared.keyWindow
let view = UIView(frame: keyWindow.frame)
view.backgroundColor = UIColor.white
view.frame = CGRect(x: 0, y: keyWindow.frame.height - 50, width: view.frame.width, height: 50)
let playerFrame = CGRect(x: 0, y: 0, width: keyWindow.frame.width, height: keyWindow.frame.height)
let playerView = PlayerView(frame: playerFrame)
playerView.item = item // Here
view.addSubview(playerView)
keyWindow.addSubview(view)
UIView.animate(withDuration: 0.5, delay: 0, usingSpringWithDamping: 1, initialSpringVelocity: 1, options: .curveEaseOut, animations:
view.frame = keyWindow.frame
, completion: _ in
playerView.startPlaying() // And here
)
在PlayerView:
class PlayerView: UIView
var item: Item?
var player: AVPlayer?
override init(frame: CGRect)
super.init(frame: frame)
backgroundColor = UIColor.black
required init?(coder aDecoder: NSCoder)
fatalError("init(coder:) has not been implemented")
func startPlaying()
let id = item?.itemId
if let url = URL(string: "http://xample.com/play.m3u?id=\(id)")
self.player = AVPlayer(url: url)
print(url)
let playerLayer = AVPlayerLayer(player: self.player)
self.layer.addSublayer(playerLayer)
playerLayer.frame = self.frame
self.player.play()
更新：
试试这个，看看会发生什么：
func startPlaying()
guard let id = id else print("** id is nil"); return // here
print("* item id = \(id)") // and here
if let url = URL(string: "http://xample.com/play.m3u?id=\(id)")
let player = AVPlayer(url: url)
print(url)
let playerLayer = AVPlayerLayer(player: player)
self.layer.addSublayer(playerLayer)
playerLayer.frame = self.frame
player.play()
更新 #2：
再次，完整的代码：
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath)
let item = items?[indexPath.item]
let playerLauncher = PlayerLauncher()
playerLauncher.showPlayer(item)
和：
class PlayerLauncher: NSObject
func showPlayer(item: Item)
if let keyWindow = UIApplication.shared.keyWindow
let view = UIView(frame: keyWindow.frame)
view.backgroundColor = UIColor.white
view.frame = CGRect(x: 0, y: keyWindow.frame.height - 50, width: view.frame.width, height: 50)
let playerFrame = CGRect(x: 0, y: 0, width: keyWindow.frame.width, height: keyWindow.frame.height)
let playerView = PlayerView(frame: playerFrame)
playerView.item = item // Here
view.addSubview(playerView)
keyWindow.addSubview(view)
UIView.animate(withDuration: 0.5, delay: 0, usingSpringWithDamping: 1, initialSpringVelocity: 1, options: .curveEaseOut, animations:
view.frame = keyWindow.frame
, completion: _ in
playerView.startPlaying() // And here
)
class PlayerView: UIView
var id: String?
var item: Item?
didSet
id = item?.itemId
print(id)
var player: AVPlayer?
override init(frame: CGRect)
super.init(frame: frame)
backgroundColor = UIColor.black
required init?(coder aDecoder: NSCoder)
fatalError("init(coder:) has not been implemented")
func startPlaying()
guard let id = id else print("** id is nil"); return // here
print("* item id = \(id)") // and here
if let url = URL(string: "http://xample.com/play.m3u?id=\(id)")
self.player = AVPlayer(url: url)
print(url)
let playerLayer = AVPlayerLayer(player: self.player)
self.layer.addSublayer(playerLayer)
playerLayer.frame = self.frame
self.player.play()
【讨论】：
您好！它仍然显示 id = nil。我需要对我的 PlayerView 类进行任何更改吗？因为这是我调用 AVPlayer 播放链接的地方。 @Mohit 您的PlayerView 似乎在初始化时开始播放，抱歉我看了一眼代码，所以您需要在init 上传递item 或更改它的工作方式。我将在我的答案中添加一些代码。
@Mohit 还有一件事。我相信您的 AVPlayer 实例应该在类中全局声明。也添加到我的答案中。
我进行了所有更改，但仍然显示 id = nil。 :(
@Mohit 这个类对我来说看起来不错，但我无法调试比这更深的东西，因为我无法自己测试它。如果它确实存在，请尝试查看collectionView 的委托方法中的item 对象。祝你好运！【参考方案2】：
您的 PlayerView 类中的 item 属性永远不会在您的初始化程序中设置。您要么需要在那里设置它，要么让任何创建 PlayerView 实例的类设置 item 属性。否则它将永远为零。
【讨论】：
感谢您的回答。你能告诉我如何创建它的实例吗？【参考方案3】：终于修好了！以下是我在代码中所做的更改：
在didSelectItem 方法中：
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath)
if let item = items?[indexPath.item]
showPlayer(item: item)
func showPlayer(item: Item)
let playerLauncher = PlayerLauncher()
playerLauncher.item = item
playerLauncher.showVideoPlayer()
在 PlayerView 中，我将 init 和 didSet 编辑为：
var item = Item()
init(frame: CGRect, item: Item)
super.init(frame: frame)
self.item = item
setupPlayerView()
backgroundColor = UIColor(white: 0.3, alpha: 1)
在setupPlayerView 方法中，我设置了itemId，最后在我刚刚添加的 PlayerLauncher 中：
var item = Item()
希望将来对某人有所帮助，因此在此处发布解决方案。非常感谢 @sCha 帮助我！
【讨论】：
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